Make assignments to dot keep an empty output section.

An assignment to dot in an output section that allocates space of
course keeps the output section.  Here, I'm changing the behaviour for
assignments that don't allocate space.  The idea is not so much to
allow people to force output of an empty section with ". = .", but
to fix cases where an otherwise empty section has padding added by an
alignment expression that changes with relaxation or .eh_frame
editing.  Such a section might have zero size before relaxation and so
be stripped incorrectly.

ld/
	* ld.texinfo (Output Section Discarding): Mention assigning to dot
	as a way of keeping otherwise empty sections.
	* ldexp.c (is_dot, is_value, is_sym_value, is_dot_ne_0,
	is_dot_plus_0, is_align_conditional): New predicates.
	(exp_fold_tree_1): Set SEC_KEEP when assigning to dot inside an
	output section, except for some special cases.
	* scripttempl/elfmicroblaze.sc: Use canonical form to align at
	end of .heap and .stack.
ld/testsuite/
	* ld-shared/elf-offset.ld: Align end of .bss with canonical form
	of ALIGN that allows an empty .bss to be removed.
	* ld-arm/arm-dyn.ld: Likewise.
	* ld-arm/arm-lib.ld: Likewise.
	* ld-elfvsb/elf-offset.ld: Likewise.
	* ld-mips-elf/mips-dyn.ld: Likewise.
	* ld-mips-elf/mips-lib.ld: Likewise.
	* ld-arm/arm-no-rel-plt.ld: Remove duplicate ALIGN.
	* ld-powerpc/vle-multiseg-1.ld: Remove ALIGN at start of section.
	ALIGN address of section instead.
	* ld-powerpc/vle-multiseg-2.ld: Likewise.
	* ld-powerpc/vle-multiseg-3.ld: Likewise.
	* ld-powerpc/vle-multiseg-4.ld: Likewise.
	* ld-powerpc/vle-multiseg-6.ld: Likewise.
	* ld-scripts/empty-aligned.d: Check section headers not program
	headers.  Remove xfail and notarget.
	* ld-scripts/empty-aligned.t: Use canonical ALIGN for end of .text2.

15 files changed, 38 insertions, 32 deletions

diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index a092428..5fdf831 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,23 @@
+2014-01-22  Alan Modra  <amodra@gmail.com>
+
+	* ld-shared/elf-offset.ld: Align end of .bss with canonical form
+	of ALIGN that allows an empty .bss to be removed.
+	* ld-arm/arm-dyn.ld: Likewise.
+	* ld-arm/arm-lib.ld: Likewise.
+	* ld-elfvsb/elf-offset.ld: Likewise.
+	* ld-mips-elf/mips-dyn.ld: Likewise.
+	* ld-mips-elf/mips-lib.ld: Likewise.
+	* ld-arm/arm-no-rel-plt.ld: Remove duplicate ALIGN.
+	* ld-powerpc/vle-multiseg-1.ld: Remove ALIGN at start of section.
+	ALIGN address of section instead.
+	* ld-powerpc/vle-multiseg-2.ld: Likewise.
+	* ld-powerpc/vle-multiseg-3.ld: Likewise.
+	* ld-powerpc/vle-multiseg-4.ld: Likewise.
+	* ld-powerpc/vle-multiseg-6.ld: Likewise.
+	* ld-scripts/empty-aligned.d: Check section headers not program
+	headers.  Remove xfail and notarget.
+	* ld-scripts/empty-aligned.t: Use canonical ALIGN for end of .text2.
+
 2014-01-21  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/16467
diff --git a/ld/testsuite/ld-arm/arm-dyn.ld b/ld/testsuite/ld-arm/arm-dyn.ld
index bef9a18..71cb4c9 100644
--- a/ld/testsuite/ld-arm/arm-dyn.ld
+++ b/ld/testsuite/ld-arm/arm-dyn.ld
@@ -149,7 +149,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = .;
diff --git a/ld/testsuite/ld-arm/arm-lib.ld b/ld/testsuite/ld-arm/arm-lib.ld
index c9482c3..f158c23 100644
--- a/ld/testsuite/ld-arm/arm-lib.ld
+++ b/ld/testsuite/ld-arm/arm-lib.ld
@@ -141,7 +141,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = .;
diff --git a/ld/testsuite/ld-arm/arm-no-rel-plt.ld b/ld/testsuite/ld-arm/arm-no-rel-plt.ld
index 439909c..d8e5c9d 100644
--- a/ld/testsuite/ld-arm/arm-no-rel-plt.ld
+++ b/ld/testsuite/ld-arm/arm-no-rel-plt.ld
@@ -181,7 +181,6 @@ SECTIONS
   }
   _bss_end__ = . ; __bss_end__ = . ;
   . = ALIGN(32 / 8);
-  . = ALIGN(32 / 8);
   __end__ = . ;
   _end = .; PROVIDE (end = .);
   /* Stabs debugging sections.  */
diff --git a/ld/testsuite/ld-elfvsb/elf-offset.ld b/ld/testsuite/ld-elfvsb/elf-offset.ld
index 7c64824..cd90bcc 100644
--- a/ld/testsuite/ld-elfvsb/elf-offset.ld
+++ b/ld/testsuite/ld-elfvsb/elf-offset.ld
@@ -131,7 +131,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = . ;
diff --git a/ld/testsuite/ld-mips-elf/mips-dyn.ld b/ld/testsuite/ld-mips-elf/mips-dyn.ld
index e4f90d2..b931e1b 100644
--- a/ld/testsuite/ld-mips-elf/mips-dyn.ld
+++ b/ld/testsuite/ld-mips-elf/mips-dyn.ld
@@ -179,7 +179,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = .;
diff --git a/ld/testsuite/ld-mips-elf/mips-lib.ld b/ld/testsuite/ld-mips-elf/mips-lib.ld
index 5073d9f..1d66c62 100644
--- a/ld/testsuite/ld-mips-elf/mips-lib.ld
+++ b/ld/testsuite/ld-mips-elf/mips-lib.ld
@@ -173,7 +173,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = .;
diff --git a/ld/testsuite/ld-powerpc/vle-multiseg-1.ld b/ld/testsuite/ld-powerpc/vle-multiseg-1.ld
index f2ff319..3fe37b9 100644
--- a/ld/testsuite/ld-powerpc/vle-multiseg-1.ld
+++ b/ld/testsuite/ld-powerpc/vle-multiseg-1.ld
@@ -4,7 +4,6 @@ SECTIONS
   { *(.data) *(.ctors) *(.dtors) *(.eh_frame) *(.jcr) }
   .text_vle	0x00001000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text_vle)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.init)
@@ -12,6 +11,6 @@ SECTIONS
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini_vle) 		
   }
-  .text_iv	. : { . = ALIGN(16); *(.text_iv) }
+  .text_iv	ALIGN(16)  : { *(.text_iv) }
   .iv_handlers	0x0001F000 : { *(.iv_handlers) }
 }
diff --git a/ld/testsuite/ld-powerpc/vle-multiseg-2.ld b/ld/testsuite/ld-powerpc/vle-multiseg-2.ld
index 2320b61..da9a79d 100644
--- a/ld/testsuite/ld-powerpc/vle-multiseg-2.ld
+++ b/ld/testsuite/ld-powerpc/vle-multiseg-2.ld
@@ -2,7 +2,6 @@ SECTIONS
 {
   .text_vle	0x00001000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text_vle)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.init)
@@ -12,6 +11,6 @@ SECTIONS
   }
   .data		0x00001400 :
   { *(.data) *(.ctors) *(.dtors) *(.eh_frame) *(.jcr) }
-  .text_iv	. : { . = ALIGN(16); *(.text_iv) }
+  .text_iv	ALIGN(16)  : { *(.text_iv) }
   .iv_handlers	0x0001F000 : { *(.iv_handlers) }
 }
diff --git a/ld/testsuite/ld-powerpc/vle-multiseg-3.ld b/ld/testsuite/ld-powerpc/vle-multiseg-3.ld
index 0ed2f44..cfb1d88 100644
--- a/ld/testsuite/ld-powerpc/vle-multiseg-3.ld
+++ b/ld/testsuite/ld-powerpc/vle-multiseg-3.ld
@@ -2,7 +2,6 @@ SECTIONS
 {
   .text_vle	0x00001000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text_vle)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.init)
@@ -10,7 +9,7 @@ SECTIONS
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini_vle) 		
   }
-  .text_iv	. : { . = ALIGN(16); *(.text_iv) }
+  .text_iv	ALIGN(16)  : { *(.text_iv) }
   .data		0x00001400 :
   { *(.data) *(.ctors) *(.dtors) *(.eh_frame) *(.jcr) }
   .iv_handlers	0x0001F000 : { *(.iv_handlers) }
diff --git a/ld/testsuite/ld-powerpc/vle-multiseg-4.ld b/ld/testsuite/ld-powerpc/vle-multiseg-4.ld
index 503fe06..2130427 100644
--- a/ld/testsuite/ld-powerpc/vle-multiseg-4.ld
+++ b/ld/testsuite/ld-powerpc/vle-multiseg-4.ld
@@ -2,7 +2,6 @@ SECTIONS
 {
   .text_vle	0x00001000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text_vle)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.init)
@@ -10,7 +9,7 @@ SECTIONS
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini_vle) 		
   }
-  .text_iv	. : { . = ALIGN(16); *(.text_iv) }
+  .text_iv	ALIGN(16)  : { *(.text_iv) }
   .iv_handlers	0x0001F000 : { *(.iv_handlers) }
   .data		0x00020400 :
   { *(.data) *(.ctors) *(.dtors) *(.eh_frame) *(.jcr) }
diff --git a/ld/testsuite/ld-powerpc/vle-multiseg-6.ld b/ld/testsuite/ld-powerpc/vle-multiseg-6.ld
index c8d88dd..2db76cc 100644
--- a/ld/testsuite/ld-powerpc/vle-multiseg-6.ld
+++ b/ld/testsuite/ld-powerpc/vle-multiseg-6.ld
@@ -16,7 +16,6 @@ SECTIONS
   }
   .text_vle	0x00001000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text*)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.init*)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.fini*)
@@ -24,14 +23,12 @@ SECTIONS
 
   .text_iv	0x100000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.text_iv)
 	INPUT_SECTION_FLAGS (SHF_PPC_VLE) *(.iv_handlers)
   } >vle_seg2
 
   .text 	0x101000 :
   {
-	. = ALIGN(16);
 	INPUT_SECTION_FLAGS (!SHF_PPC_VLE) *(.text*)
   }
 }
diff --git a/ld/testsuite/ld-scripts/empty-aligned.d b/ld/testsuite/ld-scripts/empty-aligned.d
index d9916dd..ff131eb 100644
--- a/ld/testsuite/ld-scripts/empty-aligned.d
+++ b/ld/testsuite/ld-scripts/empty-aligned.d
@@ -1,14 +1,8 @@
 #source: empty-aligned.s
 #ld: -T empty-aligned.t
-#readelf: -l --wide
-#xfail: "hppa64-*-*"
-#notarget: frv-*-*linux*
+#readelf: -S --wide
 
 #...
-Program Headers:
- +Type +Offset +VirtAddr +PhysAddr +FileSiz +MemSiz +Flg +Align
- +LOAD +0x[0-9a-f]+ 0x[0-9a-f]+ 0x[0-9a-f]+ 0x[0-9a-f]+ 0x[0-9a-f]+ [RWE ]+ +0x[0-9a-f]+
-! +LOAD .*
-#...
- +Segment Sections\.\.\.
- +00 +.text 
+.* .text .*
+!.* .text[234] .*
+#pass
diff --git a/ld/testsuite/ld-scripts/empty-aligned.t b/ld/testsuite/ld-scripts/empty-aligned.t
index e59bc20..5f6a38d 100644
--- a/ld/testsuite/ld-scripts/empty-aligned.t
+++ b/ld/testsuite/ld-scripts/empty-aligned.t
@@ -6,14 +6,14 @@ SECTIONS
   {
     *(.text1)
   }
-  /* Same for alignment at beginning and end.  */
+  /* Same for alignment at beginning and end, although we need to be
+     careful in the expression used to align.  */
   .text2 ALIGN (4096) :
   {
     *(.text2)
-    . = ALIGN (4096);
+    . = ALIGN (. != 0 ? 4096 : 1);
   }
-  /* Same for alignment just at end, although we need to be careful in
-     the expression used to align.  */
+  /* Same for alignment just at end.  */
   .text3 :
   {
     *(.text3)
diff --git a/ld/testsuite/ld-shared/elf-offset.ld b/ld/testsuite/ld-shared/elf-offset.ld
index 125d879..ee587f9 100644
--- a/ld/testsuite/ld-shared/elf-offset.ld
+++ b/ld/testsuite/ld-shared/elf-offset.ld
@@ -128,7 +128,7 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(. != 0 ? 32 / 8 : 1);
   }
   . = ALIGN(32 / 8);
   _end = . ;